1. Field of the Invention
The present invention relates to computer storage devices, such as disk drives, and, more particularly, to a self-positioning lever for opening the shutter of a removable disk cartridge upon insertion of the cartridge into the disk drive.
2. Description of the Prior Art
Disk drives for storing electronic information are found in a wide variety of computer systems, including workstations, personal computers, and laptop and notebook computers. Such disk drives can be stand-alone units that are connected to a computer system by cable, or they can be internal units that occupy a slot, or bay, in the computer system. Laptop and notebook computers have relatively small bays in which to mount internal disk drives and other peripheral devices, as compared to the much larger bays available in most workstation and personal computer housings. The relatively small size of peripheral bays found in laptop and notebook computers, can place significant constraints on the designer of internal disk drives for use in such computers. Techniques that address and overcome the problems associated with these size constraints are therefore important.
Disk drives of the type that accept removable disk cartridges have become increasingly popular. One disk drive product that has been very successful is the ZIP.TM. drive designed and manufactured by Iomega Corporation, the assignee of the present invention. ZIP.TM. drives accept removable disk cartridges that contain a flexible magnetic storage medium upon which information can be written and read. The disk-shaped storage medium is mounted on a hub that rotates freely within the cartridge. A spindle motor within the ZIP.TM. drive engages the cartridge hub when the cartridge is inserted into the drive, in order to rotate the storage medium at relatively high speeds. A shutter on the front edge of the cartridge is moved to the side by a shutter lever, during insertion into the drive, thereby exposing an opening through which the read/write heads of the drive move to access the recording surfaces of the rotating storage medium. The shutter covers the head access opening when the cartridge is outside of the drive, to prevent dust and other contaminants from entering the cartridge and settling on the recording surfaces of the storage medium.
The ZIP.TM. drive is presently available for workstations and personal computers in both stand-alone and internal configurations. In order to provide a version of the ZIP.TM. drive for use in laptop and notebook computers, the size constraints of the peripheral bays of such computers must be considered. In particular, for an internal drive to fit in the majority of laptop and notebook peripheral bays, the drive must be no longer than 135 mm. The height of the drive must be in the range of 12 to 15 mm. These dimensions place many constraints on the design of such a drive, and give rise to numerous design problems. The present invention addresses and overcomes one such problem.
In particular, because of the length constraints in designing a version of the ZIP.TM. drive for use in laptop and notebook computers, a majority of the drive chassis is occupied by the disk cartridge once it is inserted, leaving a relatively small amount of room on the chassis for other components, including the shutter lever that moves the shutter of the disk cartridge to the side during insertion, and more particularly, any form of stop that is used to position the shutter lever for proper engagement with the cartridge shutter upon initial insertion of the cartridge into the disk drive. Because space is limited, any such stop has to be located relatively close to the pivot point of the shutter lever. With a stop spaced close to the pivot point of the shutter lever, small variations in the location of the stop cause large variations in the location of the end of the lever that must engage the cartridge. If the shutter is opened too far, the tip of the lever will contact the cartridge outside of the desired capture pocket and will "jump" over that pocket, thus missing the engagement surface of the shutter completely. If the shutter is not opened far enough, the lever may again miss the capture pocket. Because of this problem, there is a need to ensure that the shutter lever is accurately positioned to engage the shutter, irrespective of the variations in initial shutter position that may result due to varying tolerances on the lever stop and pivot point. The present invention satisfies this need.